Mount Rainier's Volcanic Plumbing Unveiled with New Detailed Picture

Scientists are getting a closer look at Mount Rainier's volcanic plumbing. By measuring how fast Earth conducts electricity and seismic waves, researchers have made a detailed picture of what happens deep beneath the surface of the mountain.

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Mount Rainier, which is the tallest peak in the Cascades, is an active volcano that is predicted to erupt again. In fact, during the past 11,000 years it has erupted explosively dozens of times. That said, its last lava flows were 2,200 years ago, and the last flows of hot rock and ash were 1,100 years ago. There are, however, a few disputed reports of steam eruptions from the 1800s. This is why learning a bit more about the volcano is important in order to potentially predict how it might erupt in the future.

"This is the most direct image yet capturing the melting process that feeds magma into a crustal reservoir that eventually is tapped for eruptions," said Phil Wannamaker, one of the researchers, in a news release. "But it does not provide any information on the timing of future eruptions from Mount Rainier or other Cascade Range volcanoes."

The researchers used seismic imaging and magnetotelluric measurements, which make images by showing how electrical and magnetic fields in the ground vary due to differences in how much underground rock and fluids conduct or resist electricity.

This allowed the scientists to see that Mount Rainer's partly molten magma reservoir is located about 6 to 10 miles northwest of the volcano, which is 30 to 45 miles southeast of the Seattle-Tacoma area. In addition, the scientists found that the top of the magma reservoir is about 5 miles underground and that it appears to be between 5 to 10 miles thick.

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The findings reveal a little bit more about the volcano. More specifically, they shed light on where the magma reservoir is located, which could pave the way for future studies.